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Association Theory
Association theory (also aggregate theory) is a theory first advanced by chemist Thomas Graham in 1861 to describe the molecular structure of colloidal substances such as cellulose and starch, now understood to be polymers. Association theory postulates that such materials are solely composed of a collection of smaller molecules bound together by an unknown force. Graham termed these materials colloids. Prior to the development of macromolecular theory by Hermann Staudinger in the 1920s, which stated that individual polymers are composed of chains of covalently bonded monomers, association theory remained the most prevalent model of polymer structure in the scientific community. Importantly, although polymers consist of long chains of covalently linked molecules, the individual polymer chains can often still associate and undergo phase transitions and phase separation to form colloids, liquid crystals, solid crystals, or aggregates. For biopolymers, association leads to formati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Thomas Graham (chemist)
Thomas Graham (20 December 1805 – 11 September 1869) was a Scottish chemist known for his pioneering work in dialysis and the diffusion of gases. He is regarded as one of the founders of colloid chemistry. Life Graham was born in Glasgow, Scotland and was educated at the High School of Glasgow. Graham's father was a successful textile manufacturer, and wanted his son to enter into the Church of Scotland. Instead, defying his father's wishes, Graham became a student at the University of Glasgow in 1819. There he developed a strong interest in chemistry, studying under Professor Thomas Thomson, who was impressed and influenced by the young man. He left the university after receiving his MA in 1824. He later studied medicine at the University of Edinburgh and then briefly taught chemistry at the Glasgow University Portland Street Medical School. In 1828 he was elected a Fellow of the Royal Society of Edinburgh, his proposer was Edward Turner. He won the Society's Keith Med ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |